free hit
counters
Lotus Eclat Elite 907 engine camshaft variations - Engine & Ancilliaries/Gearbox - The Lotus Forums Jump to content
suavek

Lotus Eclat Elite 907 engine camshaft variations

Recommended Posts

Hi everyone,

Suave here from Canada - happy to join this community!  I picked up a 1979 Lotus Eclat 2.5 yrs ago and recently had the engine rebuilt, but unfortunately I cannot get it to run smoothly, and I'm hoping you guys can help!

After some research, I determined that my issue might be incorrect timing.

The engine appears to be equipped with the camshafts that have 2 grooves (see picture below, this appears to match camshaft Spec 5 as per the workshop manual). Can anyone confirm that I'm interpreting this correctly? The 2 grooves can be seen clearly between the sprocket and the cam housing.

The matching cam sprockets should have yellow timing dots as per the manual. However, my cam sprockets have the blue/red timing marks on each cam. See pic below. The blue/red timing marks are facing towards the engine (toward the rear of the car).

This would indicate that I've got non-matching camshafts and cam sprockets... can anyone confirm that my findings are correct?

Would adjustable cam sprockets solve my issue?

Any input would be greatly appreciated - I really need your help.

Lotus 907 engine blue red timing dots marks.jpg

Lotus 907 camshaft 2 grooves.jpg

Share this post


Link to post
Share on other sites

Upgrade today to remove Google ads and support TLF.

Hi and welcome.

According to the service notes the cam type and sproket dot colours are dependent on the engine serial number. The 2 prefix letters determine which spec to use.

If your car is for the American market and is 1979 it could be spec 6 or spec 7.

I suspect it has spec 6 pulleys and spec 5 camshafts. :) 

image.thumb.png.29eeabfbc31755d66a0c72511af14e74.png


It's getting there......

Share this post


Link to post
Share on other sites

Hi TAR - thank you for confirming my findings.

Since I have Spec 6 pulleys, when the blue/red timing dots are aligned I'm getting 100 degrees on the intake cam and 110 degrees on the exhaust cam.  However, according to the sheet above I should be getting 102.5 degrees on both the intake and exhaust cams (since my cams are Spec 5).  I suspect this is why my engine is not running smoothly.

How do I achieve correct timing in this case?  Please help!

Share this post


Link to post
Share on other sites

I'm no expert but I would match your pulleys with your camshafts, which I suspect would be cheaper and easier than changing the camshafts.

sjsportscars have the yellow dot pulley listed on their site at 50GBP each.

If you did that, I would expect that you may need to make some adjustments elsewhere to meet spec 5.

:) 


It's getting there......

Share this post


Link to post
Share on other sites

Thank you very much for this advice TAR - sjsportscars is the place I ordered all my new engine parts from :-)

I just placed an order for the 102.5 degree (yellow dot) pulleys from them.

I'll install these as soon as they arrive and post an update here.

Share this post


Link to post
Share on other sites

I have my cams off the car and found that the inlet has one groove i.e. No one D type and the exhaust has two ie  No five  E type. Although the car ran ok before I stripped the engine, should I change anything?

Share this post


Link to post
Share on other sites

Thats odd, your 2nd picture looks to show quite clearly that there are 2 grooves on each shank.

If the car ran fine before the engine rebuild and you are sure no parts were swapped out (camshafts or pulleys) then it must be something other than these causing your issue.

I assume you have static timing set right and have made sure that the distributor is set correctly?

Fuel delivery may also be the culprit. Were the carbs rebuilt?

:) 


It's getting there......

Share this post


Link to post
Share on other sites

Drawfiler - based on everything I read about this engine, my understanding is that different cams/cam sprockets can be used in different combinations.  If your combination allows you to set the correct timing and the engine runs fine, than I suspect things should be alright (but perhaps someone with more technical knowledge can confirm).

TAR - I received my yellow cam sprockets last week and plan to drop the car off at the engine shop tomorrow for installation.

To clarify - the engine did not run well before the rebuild.  Two of the cylinders showed really low compression, that's I had the engine rebuilt.

It appears that whoever owned the car before me may have changed either the cams or the cam sprockets and they are now mismatched.

I'll report back on this issue soon.

  • Like 1

Share this post


Link to post
Share on other sites

I will be buying some rebuild parts from Lotusbits so will get confirmation from Mike Taylor at the same time. I will put a note on here to clarify things.

Share this post


Link to post
Share on other sites
On 14 November 2017 at 00:13, suavek said:

Drawfiler - based on everything I read about this engine, my understanding is that different cams/cam sprockets can be used in different combinations.  If your combination allows you to set the correct timing and the engine runs fine, than I suspect things should be alright (but perhaps someone with more technical knowledge can confirm).

TAR - I received my yellow cam sprockets last week and plan to drop the car off at the engine shop tomorrow for installation.

To clarify - the engine did not run well before the rebuild.  Two of the cylinders showed really low compression, that's I had the engine rebuilt.

It appears that whoever owned the car before me may have changed either the cams or the cam sprockets and they are now mismatched.

I'll report back on this issue soon.

Report back please ! All sorted ??

Share this post


Link to post
Share on other sites
On 14 November 2017 at 00:13, suavek said:

Drawfiler - based on everything I read about this engine, my understanding is that different cams/cam sprockets can be used in different combinations.  If your combination allows you to set the correct timing and the engine runs fine, than I suspect things should be alright (but perhaps someone with more technical knowledge can confirm).

TAR - I received my yellow cam sprockets last week and plan to drop the car off at the engine shop tomorrow for installation.

To clarify - the engine did not run well before the rebuild.  Two of the cylinders showed really low compression, that's I had the engine rebuilt.

It appears that whoever owned the car before me may have changed either the cams or the cam sprockets and they are now mismatched.

I'll report back on this issue soon.

Report back please ! All sorted ??

Share this post


Link to post
Share on other sites

I understand that the engine will run with odd cams also the inlet and exhaust can be interchanged.

this leads me to think that the problems lie elsewhere, you have changed the cam sprockets, just ensure that they are the right way round, i.e. You have the exhaust marking facing out on the pulley on that cam but just check the key to keyway alignment on the crank, itis just possible that the keyway has widened so allowing all the timing to be late. This has happened to me on another vehicle.

i am assuming that the ignition and carbs are all ok.

peter

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


×
×
  • Create New...